Q: I saved seed from some garden vegetables and planted them with some new seed that I bought. My lettuce grew well and was delicious, but the broccoli never produced a head and the radishes did not have their distinctive flavor. One cucumber plant produced fruit that looked like a small melon but tasted like a cucumber. Are the bad plants from the seed I saved or from bad seed that I purchased?

A: Many modern vegetables are hybrid varieties. Saving and planting seed from hybrids will produce offspring with a variety of characteristics. Some will be similar to the parent plant, but most will have characteristics of earlier generations that were used to produce the hybrid.

If you want to save seed from vegetables to replant you should grow heirloom varieties. These open-pollinated non-hybrid plants usually produce offspring that are similar to the parent. It’s best to grow just one variety of a particular vegetable or plant two different varieties so they do not bloom at the same time. If two varieties cross pollinate each other, you will probably get different characteristics in the next generation if you save seed. You can visit

Q: I planted beets, carrots, spinach and radishes two months ago. They sprouted and have tiny new leaves but don’t seem to be growing. What should I do?

A: If you mixed some fertilizer into your soil before planting, there should still be some nutrients for your crops. Young seedlings have small root systems, and they may benefit from a nutritional boost. You could apply a little chemical fertilizer or an organic product like fish emulsion.

Vegetables grow more slowly in winter when the days are short and temperatures are cool. A winter garden should be located where plants will receive full sun for the whole day if possible. You can also speed up seed germination and seedling growth by using floating row cover fabric. It can be laid directly on the soil or raised a few inches above the soil on hoops of heavy-gauge wire. Use rocks, bricks or boards to hold the edges of the fabric in place. The row cover fabric traps heat and protects seedlings from insect pests.

Q: When should I plant pumpkins so they will be ready by Halloween?

A: It’s too early now to plant pumpkins. They need warm weather and soil to grow well. It takes about four months from planting to harvest. You can start planting seed in May if you live in an inland area like El Cajon, but you should wait until early June if you live near the coast.

Q: How much manure should I mix into the soil for my vegetable and flower garden?

A: Composted poultry manure is a good organic fertilizer for vegetables and flowers. At least two weeks before planting, evenly apply 2 pounds of dry poultry manure for every 10 square feet of garden soil. Mix it in 6 to 8 inches deep, then water thoroughly several times.

Steer manure has a lower concentration of plant nutrients and relatively more total salts than poultry manure. If you use it, apply 5 to 10 pounds of dry manure over 10 square feet of garden soil 2 to 4 weeks before planting. Mix it into the soil, then water periodically to leach salts out of the surface soil.

Vincent Lazaneo is an urban horticulture adviser with the University of California Cooperative Extension. Send questions for “Plants & Pests” to homeandgarden@utsandiego.com